Openldap and Thunderbird

I am new to this list and hope someone can help me.
I want to connect to an LDAP-Directory with thunderbird
mail client. Thunderbird offers me this option and I did enter
all the requested information (as I think) correctly.
There is no error shown and the connection seems to work but
there are no email addresses imported. After searching the
Internet I found out, that thunderbird wants to have a special
structure in the LDAP-Directory which I obviously don't have.

Can anyone tell me, how this structure should look like?
Which entries are needed so Thunderbird will show the record?
Has anyone experiences using Openldap and thunderbird?

To your information:
I am using thunderbird 0.7.3 under SuSE 9.1 and openldap 1.23.2.8 under
gentoo linux.